<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>

    <style>
        <!--以下两种情况都是正确的-->
        /*div{*/
            /*width: 100px;*/
            /*height: 50px;*/
            /*border: 1px solid crimson;*/
            /*border-radius: 50px 50px 0px 0px;*/
        /*}*/
        div{
            width: 100px;
            height: 50px;
            border: 10px solid crimson;
            border-radius: 100px 100px 0px 0px;
        }

        img{
            border-radius: 300px;
        }
    </style>

</head>
<body>

<div></div>

<img src="../image/pic.png" alt="">

</body>
</html>